Missing 2G only on my Galaxy s4 I9505 on lollipop

I have a problem with receiving calls and text messages due to a weak 3G signal, now I want to make my phone and force it to work on the 2G mode only, but since I am on lollipop 5.0.1 I don't have this as a choice. I tried using this code: #*#*4636#*#* but it doesn't work with me. I also tried a few apps from the play store (e.g. [Toggle Network Type 5.0](http://forum.xda-developers.com/android/apps-games/widget-toggle-network-type-5-0-xda-t2945406) which was specifically made for Lollipop) but nothing works. My phone is rooted.